One of the problems with this sort of rule is unintended consequences. Many years ago I visited the racing car museum at Donington Park. A lot of them had strange lumps on the moncoque in line with the mirrors. Anyone want to guess what they're for asked the guide?
There was a rule that nothing is allowed to stick out from the moncoque. But this made the mirrors illegal. So the lumps were there purely to make the mirrors legal.

It would depend upon how the rule was being interpreted. By strict application of the words (Literal Rule) yes. a sticker protrudes from the hull and would be a basis for disqualification. as would a boat repair to the hull. etc...if it protruded from the hull. These are clearly not the intention of the rule and this is why there is uncertainty. Ridiculous to me may be very different to ridiculous to a paddler. Hence the rule needs to be clear.

On the face of it, the literal interpretation of the rule takes us nowhere and is confusing which could lead to a wrong disqualification or the appeal of a right disqualification. So we are left with the Mischief rule. But for that to realistically to apply there will need to be a little more detail. I have suggested that a permanently fitted addition to the hull that is otherwise within the rule in terms of dimensions etc could potentially be a lawful addition. This is an argument rather than a decision so be careful.

The old fins were stuck on with tape and Evo Stick etc most of the time and were badly designed in terms of safety. The new dimensions would seem to address that. It is ruined though by any object protruding and in the mould of the hull which feels like they were added as an afterthought. to stop fins being added after manufacture. when in fact, it would probably be much better and safer if they were added after manufacture, either by the manufacturer or to a similar standard, ie glassed on and smoothly blended in without sharp ridges.

I could stick fins onto a hull and you would have to be a bloody good scrutineer to work out that they were retrofitted and not simply reinforced. In fact, I'm not sure that you could.

Colin is going to look at it with the ICF and see if we can get some clarity. Athletes want them and benefit from them. As long as they are safe, I don't see a problem myself.

I have consulted with the ICF Slalom Committee, and the interpretation for this year will continue to be a strict interpretation of the rules. Fins must be built into the mould of the boat. The ICF Chair has been asking manufacturers to provide the model name and pictures of the mould as proof they are built into the boat when manufactured.
I will confirm with the slalom committee at our next meeting, but I would expect us to follow the same logic as far as possible. So in any case where we become aware of a fin being added post moulding the competitor will be disqualified under this rule

Hon Secretary to the British Canoeing Slalom Committee( a different Id is used for personal rants and raves)

Seems silly to me that a little plastic or aluminium fin stuck on the bottom of your boat is considered a danger in a sport where there is the potential to swim down the Graveyard or Bourg and all the natural hazards you accept by doing this......

Stand up board surfers have fins on their boards and their boards are leashed to their ankles - surely when they wipe out on waves there is a good chance of the fins hitting them and yet they don't ban them.

Its a bit like the other daft rule that was brought in to increase minimum boat weights to 9kg because manufacturers could not make robust split boats lighter than 9kg. I'm still to see a split boat being used in the UK and when the GB senior team went to Oz this winter I believe they took full length boats - so what was that daft rule change all about ?

We should be looking for ways to develop our equipment to make it perform faster and better - this will make the sport more exciting and attract more interest.

At the worlds this year there will be C1 and C2 WWR boats using almost the same course all fitted with aftermarket (probably mostly home made) fins much larger than anyone seems to be wanting to use on slalom boats. WWR paddlers have managed not to injure anyone with their fins for many years. But as someone reminded me earlier in the thread, it is a mistake to assume the rule has any basis in common sense....

From my point of view I am glad that they are banning fins, not because of safety concerns, but because they are impractical on most natural courses. One of the great things about modern boats is that they are very strong, and the days of constant maintenance are a fading memory, the last thing I want on my boat is something that I am going to have to constantly repair. I am not interested enough to dissect the rules but I hope that the result is to prevent boats becoming more fragile.